1. Field of the Invention
The present invention relates, generally, to a cleaning solution composition and a method of making and using the cleaning solution composition. More particularly, the invention relates to an acidic cleaning solution composition containing an oxidizing agent, and a method of making and using the acidic oxidizing cleaning solution.
2. Background Information
The semiconductor industry employs extensive cleaning regimens in the production of various electronic components, such as printed circuit boards and devices, as well as the precursors therefor, such as chips and wafers. Various cleaning and rinsing steps are used to remove contaminants from these components during fabrication, since even minute contaminants can interfere with the operation of the electronic components. The materials used to clean the components include ultrapure water, and aqueous solutions of various cleaning agents, including acidic, neutral, and basic substances, as well as organic solvents, both polar and nonpolar. The contaminants targeted for removal from the electronic components include inorganic compounds, such as metal salts, organic substances, such as grease or oil, and particulate material. Particles can cause open or short circuits and non-integral dielectric films in semiconductor devices. Organic and inorganic contaminants, both metallic and nonmetallic, can result in poor dielectric film quality with decreased device performance and reliability. Metallic contaminants can be especially damaging. Taken as a whole, contaminants result in a large portion of yield loss in the manufacture of electronic components.
In addition, the purity of the cleaning and rinsing substances used to remove the contaminants must be controlled to prevent contamination of the electrical component being treated. Also, the containers and equipment used in the cleaning and rinsing processes must not contribute contaminants to the system. For instance, the present total allowable metal ion concentration in chemicals used for the semiconductor industry is 5 parts per billion (ppb). It is estimated that the purity of chemicals must improve 10-fold approximately every 6 years. Thus, both the chemicals used and the equipment employed to handle the chemicals must be extensively free from contaminants.
Since metal ions are particularly undesirable semiconductor contaminants, metallic containers are generally avoided for cleaning liquids. Plastic containers, and, in particular, perfluorinated organic polymer based containers, are widely used for this purpose. These containers are subject to both surface and bulk contamination where contaminants are desorbed from the surface or bulk of the perfluorinated polymer based container.
There are numerous approaches to cleaning components and many issues which must be considered in selecting the best approach. Safety and environmental concerns must be addressed, as well as the effectiveness of the cleaning technology for providing clean components. Cleaning effectiveness considerations need to include the ability to remove particles, inorganic materials, and organic materials. Cleaning agents should be easily removed from the component and not leave a substantial residue. In addition, components must dry without "spotting".
Safety concerns include cleaning agent toxicity and flammability. Environmental concerns include the release of hazardous air pollutants (HAPs), volatile organic compounds (VOCs), ozone depleting solvents (ODSs) and compounds which have a high global warming potential (GWP).
The major variables which control cleaning effectiveness are the solution chemistry (including temperature) and the use of mechanical energy. Chemistries which are commonly used include aqueous solutions (with and without surfactants), semiaqueous solutions (water and organic solvent mixtures), organic solvents, hydrofluorocarbons and co-solvent systems. Mechanical energy can be imparted to the cleaning solution using ultrasonic transducers, megasonic transducers, carbon dioxide snow, high pressure spray, and the like.
The state of the art generally includes various devices, methods and compositions for removing contaminants from components and material used to clean these components. The complexity of the selection process is described in a paper by Kanegsberg and Seelig entitled "Precision Cleaning Options for the '90s" published in Precision Cleaning '96 Proceedings, pp. 224-235.
These devices and methods are believed to have significant limitations and shortcomings. Specifically, cleaning solutions may contain corrosive, toxic and difficult to dispose of materials. An ideal cleaning solution should be easy to prepare on-site, comparatively safe and nontoxic in use, and conveniently decomposed to innocuous products for disposal.
Applicant's invention provides a cleaning solution composition, as well as a method of making and using the cleaning solution, which are believed to constitute an improvement over the prior art.